Method of and an apparatus for producing wire

Abstract

A method of and an apparatus for rolling a rod as a starting material and producing a wire of 5 mm or smaller diameter, the method and apparatus using a continuous rolling mill comprising a plurality of round-grooved four-roll stands arranged in tandem, wherein the grooved four-roll is displaced between adjacent rolling stands by 45 degrees relative to each other around the pass line and the center-to-center distance between adjacent rolling stands measured in the pass line direction is not greater than 50 times the diameter of the rod. The front end portion of the rod is fed at slow speed into the continuous rolling mill, the front end portion being guided by a front pipe to the center of the round groove, and the front end portion is wound on a coiler. After that, the rotation speed of the grooved rolls in each rolling stand is so set as to prevent slack in the rod passing through the continuous rolling mill, and the rod is rolled at high speed, without causing the rod to touch the leading pipe, to produce a wire. Each of the rolling stands that constitute the continuous rolling mill is movable in a direction perpendicular to the pass line, each rolling stand being moved for connection to or disconnection from the driving source.

What is claimed is: 
     
       1. An apparatus for rolling a rod as a stock material and producing a wire of 5 mm or smaller diameter, comprising: a continuous rolling mill for rolling the rod, comprising a plurality of round-grooved four-roll stands arranged in tandem along a pass line, each roll stand including four-rolls defining a round groove center therebetween and each of the rolls having a round roll groove, wherein a bottom position of the roll groove is displaced between adjacent rolling stands by substantially 45 degrees relative to each other around the pass line;   a distance between the round groove center of adjacent rolling stands measured in a direction along the pass line is greater than 30 times and is not greater than 50 times an average diameter of the rod passing between the rolling stands;   mounting means for mounting thereon each of the rolling stands of said continuous rolling mill and movable with each rolling stand in a direction substantially perpendicular to the pass line; and   moving means for moving said mounting means.     
     
     
       2. A wire producing apparatus as set forth in claim 1, wherein said continuous rolling mill includes at least one finishing four-roll stand.   
     
     
       3. A wire producing apparatus as set forth in claim 1, further comprising: an uncoiler for unwinding a rod wound in a coil and feeding the rod to said continuous rolling mill; and   a coiler for winding in a coil a wire obtained by rolling through said continuous rolling mill.   
     
     
       4. A wire producing apparatus as set forth in claim 3, further comprising: pressing means for pressing the coil of wire wound on said coiler;   sensing means for sensing timing of when a coil diameter on said uncoiler is reduced below a predetermined dimension; and   means for operating said pressing means in accordance with the timing sensed by said sensing means.   
     
     
       5. A wire producing apparatus as set forth in claim 1, wherein the distance between the round groove center of each adjacent pair of the rolling stands is no greater than 250 mm and the combination of the round roll groove of each of the rolls and the distance between the round groove center of each adjacent pair of the rolling stands prevents twisting of the rod as the rod travels downstream along the pass line. 
     
     
       6. A wire producing apparatus as set forth in claim 1, wherein the distance between the round groove centers of adjacent rolling stands at an outlet of the rolling mill is not greater than 50 times the average diameter of the rod passing through the adjacent rolling stands at the outlet. 
     
     
       7. An apparatus for rolling a rod as a stock material and producing a wire of 5 mm or smaller diameter, comprising: a continuous rolling mill for rolling the rod, comprising a plurality of round-grooved four-roll stands arranged in tandem along a pass line and at least one finishing four-roll stand, each roll stand including four-rolls defining a round groove center therebetween and each of the rolls having a round roll groove, wherein   a bottom position of the roll groove is displaced between adjacent rolling stands by substantially 45 degrees relative to each other around the pass line;   a distance between the round groove center of adjacent rolling stands measured in a direction along the pass line is greater than 30 times and is not greater than 50 times an average diameter of the rod passing between the rolling stands;   a common driving source for driving the rolling stands of said continuous rolling mill; and   means for connecting and disconnecting a driving force of said driving source with respect to said at least one finishing stand.   
     
     
       8. An apparatus for rolling a rod as a stock material and producing a wire of 5 mm or smaller diameter, comprising: a continuous rolling mill for rolling the rod, comprising a plurality of round-grooved four-roll stands arranged in tandem along a pass line, each roll stand including four-rolls defining a round groove center therebetween and each of the rolls having a round roll groove, wherein;   a bottom position of the roll groove is displaced between adjacent rolling stands by substantially 45 degrees relative to each other around the pass line; and   a distance between the round groove center of adjacent rolling stands measured in a direction along the pass line is greater than 30 times and is not greater than 50 times an average diameter of the rod passing between the rolling stands;   an uncoiler for unwinding a rod wound in a coil and feeding the rod to said continuous rolling mill;   a coiler for winding in a coil a wire obtained by rolling through said continuous rolling mill;   a tensioner having a tension roller for applying tension to the wire being wound on said coiler;   two bending rollers disposed at a position near a peripheral surface of said coiler and at which said tension roller is pressed against the bending rollers; and   driving means for moving said tension roller between a tension application position, where a constant tension is applied to the wire being wound, and a bending position where said tension roller is pressed against said bending rollers, wherein, just before the winding of a tail end portion of the wire, the tension roller is moved to the bending position to bend the tail end portion of the wire into a shape that matches a curvature of the coil.   
     
     
       9. A method of rolling a rod as a stock material and producing a wire of 5 mm or smaller diameter, comprising the steps of: arranging a plurality of round-grooved four-roll stands in tandem along a pass line wherein each roll stand includes four grooved rolls defining a round groove center therebetween and each of the rolls has a round roll groove, a bottom position of the roll groove being displaced between adjacent rolling stands by substantially 45 degrees relative to each other around the pass line and a distance between the round groove center of adjacent rolling stands measured in a direction along the pass line being greater than 30 times and not greater than 50 times an average diameter of the rod passing between the rolling stands;   feeding a front end portion of the rod at slow speed into the plurality of rolling stands arranged in tandem, the front end portion being guided by a leading pipe to the round groove center, and winding the front end portion around a coiler;   setting a rotation speed of the grooved rolls of the plurality of rolling stands so that the rod will not slack during rolling through the plurality of rolling stands;   feeding the rod at high speed into the plurality of rolling stands without causing the rod to touch said leading pipe;   rolling the rod through the plurality of rolling stands to produce a wire; and   winding the produced wire on said coiler.   
     
     
       10. A wire producing method as set forth in claim 9, wherein the plurality of rolling stands include at least one finishing stand and are driven by a common driving source in such a manner that all the rolling stands are driven together during a time that the front end portion of the rod is being fed while being guided by said leading pipe to the round groove center, until the front end portion is wound on said toiler, and thereafter a drive shaft of the at least one finishing stand is disconnected from said driving source and is allowed to rotate to roll the rod into a final size as the rod is passed therethrough.   
     
     
       11. A wire producing method as set forth in claim 9, wherein the plurality of rolling stands are clamped together by a clamping means, said clamping means being released, when changing a final rolled size of the rod.   
     
     
       12. A wire producing method as set forth in claim 9, wherein the wire wound on said toiler is pressed from an outer surface thereof in accordance with timing related to the rolling of a tail end of the rod being completed in the pass line.   
     
     
       13. A wire producing method as set forth in claim 9, wherein a timing at which a tail end of the rod passing a prescribed position in the pass line is detected, with which timing a rolling line speed is caused to slow down at a predetermined deceleration rate, and when the rolling line speed is reduced to a predetermined speed, the wire wound on said toiler is pressed from an outer surface thereof.   
     
     
       14. A wire producing method as set forth in claim 9, wherein while the rod is unwound from a coil wound on an uncoiler and fed into the plurality of rolling stands, a timing at which a diameter of the coil on said uncoiler decreasing below a predetermined dimension is detected, with which timing a rolling line speed is caused to slow down at a predetermined deceleration rate, and when the rolling line speed is reduced to a predetermined speed, the wire wound on said coiler is pressed from an outer surface thereof.   
     
     
       15. A wire producing method as set forth in claim 9, wherein the distance between the round groove center of each adjacent pair of the rolling stands is no greater than 250 mm and the combination of the round roll groove of each of the rolls and the distance between the round groove center of each adjacent pair of the rolling stands prevents twisting of the rod as the rod travels downstream along the pass line. 
     
     
       16. A wire producing method as set forth in claim 9, wherein the distance between the round groove centers of adjacent rolling stands at an outlet of the rolling stands is not greater than 50 times the average diameter of the rod passing through the adjacent rolling stands at the outlet.